1. Field of the Invention
The present invention relates to the IEEE 1394 network, and more particularly a method of optimizing the topology of the IEEE 1394 serial bus.
2. Description of the Related Art
The IEEE 1394 is a multimedia interface of the next generation for enabling information exchange among various multimedia instruments according to the specification prepared by IEEE (Institute of Electrical and Electronics Engineers), which provides a serial bus standard to enable communication of audio and video data among multimedia instruments such as HD-TV, DVD and DVC, differing from the conventional interface only to allow the connection between the personal computer and peripheral devices such as a mouse, a printer, a scanner, etc. The IEEE 1394 technology has been rapidly developed by engineers practicing electronics, communications and computer technologies, presently providing for a high data transmission speed of 400 Mbps, a plug & play system, 63 nodes on a single bus, etc.
In order to optimize the topology of the IEEE 1394 serial bus the following three methods may be used. First, the cable topology is reconstructed so as to reduce the hop number. Second, the cable topology is reconstructed so as to arrange the nodes of the same speed capacity adjacent to each other. Third, the gap count is optimized for the present cable topology. However, the IEEE 1394 specification only defines the third method to reduce the gap count according to the maximum hop number of the present cable topology.
In the IEEE 1394 cable environment, the nodes are connected in the form of a daisy-chain, as shown in FIG. 1 illustrating the structure of the IEEE 1394 serial bus network using three ports. In the drawing, reference numerals 10, 30 and 40 represent nodes, and 20 represents hop. There are shown 36 nodes existing in a single bus, where the maximum hop number between two nodes, for example, the node numbered 1 and the node numbered 17, becomes 16. In such IEEE 1394 serial bus network as shown in FIG. 1, if there occurs a transmission speed difference between the adjacent nodes, the efficiency of the high speed node (for example, 200 Mbps) may be reduced by the low speed node (for example, 100 Mbps). Hence, in the IEEE 1394 cable environment, it is necessary to connect together all the nodes existing in a single bus and construct the topology for keeping the speed capacity of each node as great as possible.